Just be yourself and try not to think it over too much. Just relax and don't think about expectations. You are going out with him; just let it happen. Just relax. If it works, it works, and if it doesn't work then it doesn't.
If he knows who you both are and what you are looking for, then a lot of the traditional game playing should be out of the way. Just relax and get to know each other. Get to know him, and let him get to know you.